I'm having a similar problem. Prior to the froyo update, I rarely had a problem with bluetooth connecting to the car. After the update, the bluetooth would not connect at all to the car. I deleted the phone and resynced, but it was flaky on the connection (i.e connecting, dropping, connecting). I restarted the phone and it connected. The next day the bluetooth connected to the car and showed it was connected to a call, but there was no sound and it was still coming through the phone. I restarted the bluetooth on the phone, it connected again, I started a call through the car, and then it dropped out again back to the phone. Then it disconnected my phone call.
At this point, having tinkered with the phone for over 6 months, I'm done with Android. It requires too many updates, too much research, and too much troubleshooting. To me, it's turning into MS Windows, constantly requiring updates. I enjoy customizing a new phone, but this is way beyond a reasonable expectation of time trying to ensure the phone is stable. The froyo update was held up for over 6 months, building up frustration by users that thought it would fix stability issues, then we were hit with the GPS problem that required a patch, and the now the froyo update that killed battery time (again-hours wasted researching online only to discover froyo reset all the syncs to update immediately and the display "power saving mode" was constantly trying to analyze the brightness, thus killing the battery in less than 2 hours), and the now the bluetooth issue.
I just wasted 1 1/2 to 2 hours hard resetting (again), reloading all backups, and resetting accounts. Now, I have to turn around and do the same to my wife's phone, taking away quality time with the family.
If the hard reset does not correct the bluetooth issue I'm taking both phones back to Verizon for a phone with a mature, stable operating system other than Android. I've read multiple posts that state Verizon tech support said to do a hard reset, but to me that is not a reasonable answer for every issue do to the amount of time it takes to reconfigure everything even if all apps are backed up.
